[Xen-devel] [PATCH v8 06/27] ARM: GICv3: enable ITS and LPIs on the host

[Andre Przywara <andre.przywara@xxxxxxx>]

Now that the host part of the ITS code is in place, we can enable the
ITS and also LPIs on each redistributor to get the show rolling.
At this point there would be no LPIs mapped, as guests don't know about
the ITS yet.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 xen/arch/arm/gic-v3-its.c |  4 ++++
 xen/arch/arm/gic-v3.c     | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
index 07280b3..aebc257 100644
--- a/xen/arch/arm/gic-v3-its.c
+++ b/xen/arch/arm/gic-v3-its.c
@@ -505,6 +505,10 @@ static int gicv3_its_init_single_its(struct host_its 
*hw_its)
         return -ENOMEM;
     writeq_relaxed(0, hw_its->its_base + GITS_CWRITER);
 
+    /* Now enable interrupt translation and command processing on that ITS. */
+    reg = readl_relaxed(hw_its->its_base + GITS_CTLR);
+    writel_relaxed(reg | GITS_CTLR_ENABLE, hw_its->its_base + GITS_CTLR);
+
     return 0;
 }
 
diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index 8140c5f..d539d6c 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -620,6 +620,21 @@ static int gicv3_enable_redist(void)
     return 0;
 }
 
+/* Enable LPIs on this redistributor (only useful when the host has an ITS). */
+static bool gicv3_enable_lpis(void)
+{
+    uint32_t val;
+
+    val = readl_relaxed(GICD_RDIST_BASE + GICR_TYPER);
+    if ( !(val & GICR_TYPER_PLPIS) )
+        return false;
+
+    val = readl_relaxed(GICD_RDIST_BASE + GICR_CTLR);
+    writel_relaxed(val | GICR_CTLR_ENABLE_LPIS, GICD_RDIST_BASE + GICR_CTLR);
+
+    return true;
+}
+
 static int __init gicv3_populate_rdist(void)
 {
     int i;
@@ -731,11 +746,14 @@ static int gicv3_cpu_init(void)
     if ( gicv3_enable_redist() )
         return -ENODEV;
 
+    /* If the host has any ITSes, enable LPIs now. */
     if ( gicv3_its_host_has_its() )
     {
         ret = gicv3_its_setup_collection(smp_processor_id());
         if ( ret )
             return ret;
+        if ( !gicv3_enable_lpis() )
+            return -EBUSY;
     }
 
     /* Set priority on PPI and SGI interrupts */
-- 
2.8.2


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